Metalworking apparatus



Feb, 7, 190 F. A. FRITZSCH METAL WORKING APPARATUS 4 Sheets-Sheet 1Filed June 14, 1946 I N VEN TOR.

Feb. 7, 1950 Filed June 14, 1946 F. A. FRITZSCH 2,496,663

METAL WORKING APPARATUS 4 Sheets-Sheet 2,

4 Sheets-Sheet 3 F. A. FRITZSCH METAL WORKING APPARATUS Feb. 7, 1950Filed June 14, 1946 mm Q1 4 Sheets-sheet 4 F. A. FRITZSCH METAL WORKINGAPPARATUS Feb I,} 1950 Filed June 14, 1946 Patented Feb. 7, 1950 UNITEDSTATES PATENT OFFICE 'METALWORKING APPARATUS LFrankVA. .Fritzsch,Cincinnati, Ohio, aassignor to The :Lodge and Shipley Company,Cincinnati,

Ohio, a corporation of Ohio Application June 14, 1946, Serial No.676,735

dillaims. :1 'This invention relates :to metal working, and 'isconcerned particularly :with operations upon shafts of a type whichheretofore'were shaped :at considerable expense and with questionableaccuracy, using methods and apparatus not well adapted to the work. 7

One of the-"objects of the-invention is to provide a greatly improvedmethod and means of shaping a complex shaft, whereby production time andcosts "are substantially reduced, with a 'maked improvement in quality,finish, and accuracy resulting.

Another object is to provide -a-novel method and means for rapid turning"and forming of shafts having sections of different diameters,

"with the elimination of steady rests and-similar auxiliary supportsheretofore "considered necessary to proper production of such shafts;the

- improved method'and apparatus making possible *the removal of metalat'ahigh-rate in the'turn- :ing and forming of the shaft, withoutchatter and the danger-of springing the shaft.

Another object of the invention is to'provide a special tailstockassembly for a lathe, adapted to facilitate and expedite the productionof complex shafts of the character mentioned'above.

The foregoing and other objects are attained by'the meansdescribedherein-and'illustrated in the accompanying drawings, in-which:

Fig. 1 is-an elevational viewofa lathe embody 'ing the means of theinvention.

Fig. 2 is an enlarged elevational view of the tailstock end of thelathe, parts being broken away.

Fig. 3 is an enlarged cross-sectional view taken on line 3-3 of Fig.2.

Figs. 4 to '12 inclusive,'are diagrammatic views illustrating arepresentative succession of operation steps constituting the method ofthe in- 'vention.

:Fig. 13 is a side view of -a modified headstock chuck arrangementforthe machine.

Inthe production of large shafts-characterized by frequent changes ofcontour and diameter,

such as the cam-shaftsof Diesel engines and the like, it has beencustomary heretofore to-prepare blanks by means of drop forging andturning processes, which presented-various disadvantages andobjectionable limitations. in-the case of the drop forging process, thedies were "very expensive and many instances they were discarded longbefore the expiration of their useful life period because of the limiteddemand for such L'blanks, or the ifrequencymf changes :inthedesignthereof. The fforging die costs -'thereby were and tedious, resulting inhigh cost per unit manufactured.

To overcome the disadvantages above mentioned, long shafts weresometimes made-up of sections bolted or otherwise joined together aftermachining, but such procedure likewise increased tne costof productionbecauseof the additional .20-

handling and assembling stepsinvolved.

The method and means of the present invention are effective forobviating all ofthe common disadvantages .and limitations of the priorprocesses, with the result that production time and labor costsare'materially reduced, while at the same time the accuracy and finishof the blanks produced are greatly enhanced, without ahigh percentage ofrejects occurring. By means :of :this invention, bar stock of any lengthcan be used to advantage for making a one-piece blank, and all excessstock is removed at maximum speed *to produce the blank quickly andeiiiciently vwithout theaid of special supports at thecutting or formingtools. No limitations or restrictions on production are imposed, otherthan the horsepower 'of the machine and the life of its cutting tools.Maximum chip removal is provided for throughout the procedure, as thework-piece is always gripped at its largest diam- -:.eter and is firmlysupported at all times without the use of a steady rest or otherauxiliary attachment, while the cutting is performed close to thedriving spindle and chuck of the machine.

One feature of the invention which is responsible for the desirableresults obtained, is

the special tailstock or work-piece positioner of Figs. 2 and 3, whichperforms the functions of the steady rest or other auxiliary work-piecesupport throughout the turning and forming-operations upon the blank,while permitting the tools to operate in close proximity-to the drivingspindle chuck. The improved tailstock performs other functions also,with respect to positioning and ,re-positioning the work-piece relativeto the tools, in aprecise andexpeditiousmanner.

The machine of the invention is a lathe comprising the usual bed Ithaving carriage ways l5-l5 and tailstock ways l6l6 extendinglongitudinally of the bed and adapted to support and guide the carriageI! and the tailstock indicated generally at l8. The usual leadscrew l9and feed rod 20 are provided for moving the carriage longitudinally ofthe bed, and for moving the tool slide or slides 21 transversely of thebed, in accordance with common practice. In addition to the power meansfor so actuating the carriage and the tool slides, these elements may bemoved manually by means of hand wheels or other devices 22 and 23. As isusual in machines of this type, a mechanical apron control rod 24 may beprovided, including length feed stops 25 and 26 which are adjustablealong the rod, and which function to automatically limit the extent ofcarriage movement in opposite directions longitudinally of the bed,through the agency of trip means located within a trip box 27. Inaddition to the adjustable automatic length feed device, the machine maybe equipped also with means for automatically advancing and retractingthe tools relative to the work-piece, thereby to render the turning andforming operations of the tools completely automatic, if desired.

The machine is provided with the usual feed box 28 and quick change gearbox 29, including the means necessary for the automatic functions aboverelated. The mechanisms for performing said functions are well known inthe art and form no part of the present invention, wherefore it isbelieved unnecessary to describe them in detail here.

The headstock of the machine is indicated generally upon Fig. l by thecharacter 80, and in- .cludes the gears necessary to drive at selectivespeeds the hollow spindle 3|. The spindle at its inner end may befurnished with a chuck 32 to firmly grip and rotate a work-piece A whichextends within the bore of the spindle. Chuck 32 may be of any approvedtype. although as shown in Fig. l by way of example, it may be aconventional chuck operated by fluid pressure conveyed to an operatingcylinder 34A by means of the supply pipe 34 and controlled by means of avalve 35. The work-piece on occasion may project outwardly beyond theheadstock as indicated upon Fig. 13, in which case it may be desirableto furnish a second chuck 33 applied to the machine at the outer end ofthe hollow spindle. Chuck 33, which is applied only when the workpieceis very long and extends well to the left of the headstock, is hereshown as one manually operated through the agency of a squared operatingshaft 33A. Chuck 32B may be similarly operated. Chucks operated bypressure of air or liquid and chucks which are mechanically operated,are well known in the art wherefore they are illustrated only generallyupon the accompanying drawings,

The several turning and forming tools are indicated by the characters 36and 31, and these are securely mounted upon a turret 38 carried by thetool slide '2 l the turret being operative to present any one of severaltools to the work-piece. If desired, the carriage may be provided with aplurality of turrets, or with tools arranged to engage the work-piecefrom the rear, as well as at the front of the carriage. As will be notedby referring to Fig. l, the turning and forming of the work-piece areperformed by the turret tools at a location close to the chuck 32, sothat chatter is eliminated irrespectiveof the depth to which,

the tools enter the work-piece. The turret is rotatable upon the crossfeed slide to present the different tools to the work, as will beunderstood. Grooves cut in the work-piece by the tools, are indicated at39.

In performing the method of the present invention, the reduced leadingend 40 of the workpiece is gripped by means of a chuck 4| mounted uponthe inner" end of the tailstock spindle 42, the chuck and spindle beingrotatable with the work-piece. This chuck may be of any approved type,although as illustrated herein by way of example, it is operated bymeans of air or liquid under pressure fed thereto by a supply line orpipe 43 and controlled by means of a suitable valve 44. A pipe 45conveys the fluid under pressure to a coupling 46 at the rear of thespindle, and from this coupling the fluid under pressure is conveyed toa cylinder Ml embracing a piston which actuates the chuck ll. The fluidpressure feed line 43, or some part thereof, preferably is made flexibleto permit sliding of the tailstock lengthwise ofv the bed of themachine. Sliding movement of the tailstock maybe effected in anysuitable manner, as by means of a hand wheel 4'! arranged to rotate amiter gear 48 which is in constant mesh with a second miter gear 49 thatthreadedly engages a longitudinal screw shaft 50 extending lengthwise ofthe machine bed. Screw shaft 50 may be a stationary shaft for thepurposes of the present invention, although in some instances this shaftmay be power rotated by mechanism located upon the bed of the machinefor power shifting of the tailstock. Throughout the followingdescription, it will be assumed that screw shaft 50 is a normallystationary part. Obvious equivalents for movement of the tailstock wouldbe a rack and pinion arrangement, or means in the form of a pneumatic orhydraulic cylinder and piston constructed to afford the length of strokerequired for maximum travel of the tailstock. These equivalent devicesand others of common design are contemplated within the scope of thedisclosure, as they are well known and obviously adaptable for shiftingthe tailstock as required.

The tailstock comprises the spindle housing 18,

and a separate tailstock carriage or base 5| upon which the spindlehousing is guided for sliding movement by means of the dovetail 52. Bymeans of a suitable clamp or binder mechanism, the spindle housing maybe firmly fixed relative to the carriage or base. In the exampleillustrated, the binding or clamping means may be in the form of a shaft53 extending transversely of the spindle housing for rotation within thebore 54. One end Oif shaft 53 may carry a binder or clamp lever 55adapted to apply force at one side of the spindle housing, while theopposed threaded end 56 of the shaft threadedly engages a large clampblock 51 disposed along the opposite side of the spindle housing. Clampblock 57 is held against rotation in any suitable manner, and it will benoted that the action of the binder is to pull both sides of the spindlehousing toward the dovetail, with spreading of the clamping force over asubstantial area. This construction prevents undue distortion of theparts, and ensures efiicient repeated clamping over a long period oftime without injury to the dovetail guide. Release of the clamp orbinder mechanism by means .of lever 55 enables the tailstock housing tobe with a plurality of clamping nuts 58 which are accessible at oppositesides :of the "carriage to tightly draw up one or more clamp bars 59 inwhich the lower ends of the clamp screws or bolts 60 are anchored.Tightening of the clamp nuts the dovetail guides 52, relative to thebase :or carriage without disturbing a predetermined seti ting of thelatter upon the bed of the machine.

In accordance with the present .invention, it

.is desirable that the tailstock spindle housing be made quicklyretractable lengthwise of the base or carriage 5|, through a successionof steps, the steps being spaced apart predetermined distances inconformity with predetermined tool operations to be imposed upon thework-piece. Accordingly, it is desirable that a pattern be establishedand applied to the tailstock structure for predetermining the shiftingmovements of the tailstock, its chuck M, and the work-piece gripped bysaid chuck. That is to say, the method contemplates drawing thework-piece through the hollow spindle of the headstock and past thetools, with a succession of steps or movements dependent upon thelocations at which the work-piece is to be machined.

For accomplishing this purpose, there is provided a stop bar 52 notchedor otherwise provided with a series of abutments 63 formedat the upperedge 64 of the bar. Since the stop bar is in reality a pattern ortemplate, it will in every instance be notched to suit a particular job.In the exemplification illustrated, the distance between successivenotches or abutments in the upperedge of bar 62 are spaced apart incorrespondency with the distance between the grooves to be formed in thework-piece, as illustrated at 39-49 of Fig. 1. use, is fixed to one sideof the tailstock carriage or base 5!, with its edge 64 uppermost and insubstantial parallelism with the bed of the machine. The notches orabutments are adapted to be engaged by a plunger 65 carriedby thetailstock spindle housing, so that when the plunger is in engagementwith any one of the abutments of the stop bar, retraction of thetailstock housing away from the headstock will be definitely precluded.Thus, the plunger-5E may be dropped .into the various notches insuccession, to limit the extent of withdrawal of the work-piece from thehollow spindle of the headstock, and the withdrawal steps or movementswill be determined by the distance between successive notches orabutments 63 of the stop bar. Referring to Fig. 2, by way of example, itwill be seen that the tailstock is locked by plunger 65, at the secondlast notch of the stop bar, work having been performed upon thework-piece A at each of the five preceding notches or abutments to theleft .of the plunger. Since there isbut one additional notch at theright of the plunger, it is evident that only one more operation uponthe work-piece is required in order to meet the specifications.Therefore, upon completion of the operation being performed while theplunger-is in thesec- 0nd last notch of the stop bar, the operator ofthe machine will lift the plunger momentarily, :move the tailstock tothei'right until the plunger The bar 62, when the machine is in lit.

seats within the lastznotch or abutment 63, and

"then clamp the tailstock tothe carriage or base :51 preparatory toperforming the last machining :operation upon the work-piece. As long asthe said machining operation is in progress as the result of automaticror manual carriage and tool movements, the :tailstock will remain atthe position determined by one of the abutments or notchese63.

The stop bar may be mounted upon the tail- :stock base orcarriageiin'any suitable manner. As disclosed herein by way of example,the stop bar 62 provided with thenecessary notches or abut- 'ments, islaid fiatwise against a seat 66 formed at oneside of the carriage orbase, and may be held inplace by means of a-series of bolts or otherfasteners .61. To provide for slight longitudinal adjustment, the boltsor fasteners may pass through-elongated slots .68 formed in the materialof the stop bar. Micrometric longitudinal adjustments of the stop barmay be desired in some instances, and .in :such case it may be desirableto provideanadjusting screw-69 .in endwise abutment with one end of thestopbar, the screw being threaded through a stationary block in appliedto the side of the tailstock carriage or base. The screw may be lockedin adjusted positions by means of a nut or other expedient l l.

At the opposite or forward end of th stop bar, an end stop or abutment12 may be furnished, if desired, for locating the tailstock and clutch4| relative to the forward end .of its carriage *or base 5 I ,andconsequentlylocating the work-piece initially relative to the cuttingtools. This end stop preferably, though not necessarily, may be formedfrom a separate piece 13 fixed to the carriage by means of screws orbolts M which need not-be disturbed by application and removal of stopbar 62. For the details of plunger 65 and its supporting means,reference may be had to Figs. 2 and 3 wherein 14 indicates a housing forthe plunger, said housing being provided with a vertical bore or way 15to accommodate the plunger and permit its shifting vertically into andfrom the notches of the stop bar. The plunger may be lifted manually bymeans of a handle or finger piece '16, theinner end of which hassuitable connection with the plunger, as by means of a ring .or collar11 surrounding a reduced portion of the plunger. The plunger preferablyis non-rotatable in the bore 55, and ring 11 has limited rotationalmovement relative to the plunger, so that the lifter l6 may be elevatedmanually andthereafter thrown over slightly into a bayonet slot .18formed at the upper end of the vertical slot 19 in the side of housingit. By means of the bayonet slot or latch, the plunger .may be retained.in an elevated position above the stop bar, so as to be inoperative tolimit shiftinglmovements of the tailstock whenever free tailstockmovements are necessary or desirable. When using the stop bar, however,as a means .to automatically position th work-piece relative to thecutting tools, the lifter 16 is to be slid in bar between successiveabutments. The plunger may be forced against the upper edge of thestop'barby means of alspring .80, if desired, the spring being compressedbetween the upper end of the plunger .and the lower face ofa screw 8|threaded into the upperend o'fthe plungerbore;

From the foregoing, it will be understood that successive shiftingmovements of the tailsto'el:

:spindle' housing to theright, is determined by the location of thenotches or abutments 63 upon the stop bar 62.

1 spindle housing to the left may be limited by the forward abutment orstop 12. Movements in either direction, of course, may be precluded bytightening the binder clamp by means of lever 55.

The tailstock of the invention preferably is furnished with a guard toprevent an accumulation of chips and other foreign substances upon thescrew shaft 50 and other vital parts of the tailstock assembly thatrequire protection against scoring and premature Wear. The chip guard asherein disclosed comprises a flexible curtain which may be in the formof a band or ribbon of sheet bronze, steel, or other material. The upperreach of the curtain or band is indicated at 83, and will be seen torest upon opposed parallel ledges 84 formed upon the upper face of thetailstock carriage, between the dovetails 52. The side edges of thecurtain fit snugly within the confines of the ledges, so that foreignsubstance may not enter beneath the curtain at its opposite side edges,as the curtain travels lengthwise in contact with the surfaces 84.

The curtain has a free end 85 which is anchored to the slidabletailstock spindle housing in any suitable manner, as by means of roundedsqueeze blocks 86 between which the curtain material is clamped by meansof screws or other fasteners 81. The edges of the squeeze blocks arecurved or rounded as indicated, to prevent sharply bending the materialof the curtain, and thereby possibly weakening same.

At the extreme forward end of the tailstock carriage or base a pair ofrotatable rollers 88 and 89 provides means for guiding the curtaindownwardly then rearwardly, so that the lower reach 90 will be directedto the rear end of the carriage or base, where a third roller 9!furnishes the necessary support at that location. From roller 9i, thecurtain may pass over additional rollers 92 and 93, and from the latterit extends forwardly to a squeeze block or anchorage 94 provided at therear end of the slidable tailstock spindle housing. Between theanchorage 94 and the roller 93, the curtain 83 rests upon ledges similarto those indicated at 84 of Fig. 3, and may slide thereon as the spindlehousing is shifted lengthwise of the tailstock base or carriage 5!.

Since the slidable tailstock spindle housing may at times be moved to anextreme position toward the headstock of the machine, it may overhangthe forward end of the carriage or base at roller 88, and in theoverhung position it is quite possible that the squeeze blocks 86 may bedisposed to the left of roller 88. It may readily be appreciated thatunder such circumstances the curtain 84 may have to lengthen, and forthis reason a compensator is provided in the form of a swinging tensionarm locatedat the extreme right hand end of the base or carriage. Thetensioning means may be in the form of an end plate 95 securely fixed tothe rear of the carriage or base, said plate carrying a rearwardlyextended arm 96 having a journal 91 for swingingly supporting adepending tensioning arm 98. The tensioning arm carries the roller 92,and is normally urged into counterclockwise rotation about its pivotshaft 99 in any suitable manner, as by means of a counterweight I00which is adjustable along a counterbalance rod or arm lill. As will bereadily appreciated, the yielding tension established by means of thecounterweight, might alternatively be obtained with the use of asuitable spring or other equivalent means. It will be understood fromthe foregoing, that the flexible curtain will always be maintained in ataut condition by means of the tensioning mechanism located at the rearend of the tailstock carriage or base. Rollers 9| and 93 are rotatablymounted upon the tailstock carriage or base 51, whereas roller 92 isapplied to the swinging end of the tensioning arm 98. When the slidablespindle housing is moved to the left to such an extent that the squeezeblocks 86-86 pass beyond the roller 88, curtain 83 will be so extendedas to draw the roller 92 toward the end plate 95, in opposition to theyielding resistance of the tensioning means including the weight 199.Curtain 83 may be constructed of any suitable material having thenecessary flexibility and durability to withstand wear imposed bymovements of the tailstock spindle housing. It will necessarily benon-porous or impermeable to such extent as to preclude chips and otherforeign materials from reaching the screw shaft and such other operatingmechanism as is located beneath the spindle housing [8.

Figs. 4 to 12 inclusive represent in chronological order, the principalsteps employed in the present method of fabricating a shaft which hasnumerous changes of contour, utilizing the machine of Figs. 1, 2 and 3.By Way of example, and without limiting the invention thereto, thefollowing explanation is given to indicate the method steps andoperations which are typical in the production of a large cam shaft,such as may be used in Diesel engines or the like.

Referring to Fig. 4, the work-piece A in rod or bar form has been loadedinto the hollow spindle and projects through chuck 32 toward the chuck4|. Chuck M at this time does not grip the work-piece, but is usedmerely as a pusher to properly locate the work-piece relative to tool36, the chuck 32 being released meanwhile. Stop 12 initially determinesthe position of the Work-piece relative to the tools, by limiting themovement of the tailstock toward the headstock. This stop accordingly isto be fashioned or located to conform with the work-piecespecifications, as in the case of the stop bar notches previouslydescribed. Once the workpiece has been initially located as stated, theassembly I8 is retracted to the Fig. 5 position, and chuck 32 is thenactuated to grip and rotate the work-piece. Fig. 5 shows the firstforming out being made by tool 36 close to chuck 32, to produce areduced end upon the work-piece.

In Fig. 6, a second cut is being completed by the forming tool, likewisein close proximity to the chuck. Both of these forming operations may beperformed without use of the tailstock, which is shown standing at restin spaced relationship to the work-piece.

In the illustration of Fig. 7, the tool has been withdrawn from theWork-piece upon completion of its forming operation, and the tailstockspindle housing has been moved to the left along its carriage or base,to an extent necessary for subjecting the reduced end of the work-pieceto the grip of the tailstock chuck 4!. With the chuck 4| gripping theend of the work-piece, and the grip of chuck 32 released, the tailstockhousing is moved to the right until its plunger 651 drops into andengages the first notch or abutment 63 beyond the end stop'l2',thereby-- to=exactly position the work-piece 'relativeto turret andchuck 3-2' will be released, and the plunger 65' momentarily lifted aspreviously explained, to

permit shifting movement of the tailstock to the third notch or abutmentof stop bar 62, which results in repositioning thework-piece so thattool 36 may perform the forming operation il-' lustrated by Fig. 9. Aswill be understood, the tailstock and the chucks will'be firmly setimmediately prior to engagement of tool 36 with the work-piece.

Following the operation depicted by Fig. 9, the entire procedure may berepeated to complete another forming operation as at I02, and when thisoperation is completed the tailstock may be moved further to the right,upon release of chuck 32, to position the work-piece so that" theoperation indicated at I03 may be performedby tool 31. It should benoted'that the lineal extent of operation I03 corresponds to thedistance between notches or abutments H35 of the stop bar. The distancesbetween notches or abutments of the stop bar, as previously explained,are established by the specifications to which the work-piece shall beturned and formed.

The illustration of Fig. '11 indicates an operation being performedsubsequently to operation I03, it being noted that the tailstock hasbeen moved tothe right a distance of one additional notch or abutmentbeyond I05.

As shown in Fig. 12, the last operation upon the work-piece is beingperformed, the plunger 65 having been lodged in the last notch of thestop bar. If the work-piece called for an additional forming operationsimilar to I02 of Fig. 10, the stop bar of Fig. 12 would carry anadditional notch or abutment to the right of plunger 65, and from-thisit will be understood that the stop bar might be of any length, andprovided with any given number of notches or abutments correspondingwith the number of machining operations to be performed upon thework-piece.

It will be noted by referring to Fig. 12, thatv the work-piece has beenwithdrawn from the hollow spindle of the headstock, to a point at whichits trailing end IDS is quite close to the chuck 32. The work-pieceobviously might be withdrawn even farther, if desired, without removingit from the grip of the headstock chuck 32, so that it becomes evidentthat turning and forming operations may be performed upon the work-piecepractically to the very end I06. It may be appreciated, moreover, thatthe repetition of steps depicted by Figs. 4 to 12 inclusive may becontinued limited only by the length of the machine bed and the travelof the tailstock in a direction away from the headstock chuck of themachine. The stop bar 62, of course, can be made in any length, andprovided with any Hi l and number of notches'or abutments corresponding"to the specifications of the work-piece to be machined.

From all of the foregoing, it should readily be apparent that-theturret-may carry any required number of forming and turning tools, andthat theywill always engage the work-piece at a location close to theheadstock chuck 32;

Whenever the tailstock is shifted for presentingnew sections of thework-piece to the tools,

chuck 3-2 or any additional chucks such as. 33: carried by the headstockspindle will be released, as the tailstock chuckretains its grip uponthe work-piece to withdraw the latter through the.

-1 hollow spindle of the headstock. The extent of withdrawal, aspreviously explained, is determined solely by the relative spacings ofthe stop.

bar notches or abutments. The advancing, retracting, and longitudinalmovements of thetools relative to the workpiece may be performed eithermanually or automatically, as may be desired, or within'the capabilitiesof theautomatic cross feed and length feed control mechanisms of themachine. Application and removal ofthe work-piece to and from themachine may be eifected by means of a hoist or other conventionalexpedient, as will be evident in the light of the foregoing description.

As will be manifest to those skilled inthe art to which the inventionappertains, various modificationsand changes in structural details ofthe parts and mechanisms herein disclosed may spindle, rather than atthe exit end thereof, to

perform the function of successively positioning the work-piece relativeto the tool means, it might not properly be'regarded as a tailstockwithin the commonly accepted meaning of the- 'term. The misnomer mightapply also should chuck M be power rotated by means of a motor andthereby caused to rotate the work-piece, this being a perfectly feasibleproposition as will be understood. For the reasons stated, therefore,the

part or assembly herein referred to for convenience of description as atailstock, might not under all circumstances be properly classed as atailstock within the strict definition of the term, and this fact is tobe taken into account when construing the claim terminology.

What is claimed is:

1. A machine tool comprising in combination, a rotary chuck having anopening for the reception of an elongated workpiece to be machined atpredetermined spaced areas along the length thereof, said chuckincluding releasable gripping means to enforce rotation of the workpiecewith the chuck while precluding longitudinal shifting of the workpiece,tool means located in close proximity to the chuck and operative toshape the rotating workpiece, a workpiece positioning support shiftabletoward and from the chuck and including a second rotary chuck in axialalignment with the workpiece, releasable gripping means on the secondchuck for grasping an advancing end of the workpiece to move the latterthrough the first chuck when released, said second chuck having a closedend for abutting an end of the workpiece, and stop means forsuccessively limiting retractileshifting movements of said positioningsupport, constituting a bar provided with abutments spaced apart incorrespondency with specified spacings between areas of the workpiece tobe machined, a cooperative plunger to engage the abutments, and meansmounting the aforesaid constituents of the stop means, one upon theworkpiece positioning support and the other upon a relatively stationarypart of the machine.

2. A machine tool comprising in combination, a rotary chuck having anopening for the reception of an elongated workpiece to be machined atpredetermined spaced areas along the length thereof, said chuckincluding releasable gripping means to enforce rotation of the workpiecewith the chuck while precluding longitudinal shifting of the workpiece,tool means located in close proximity to the chuck and operative toshape the rotating workpiece, a workpiece positioning support shiftabletoward and from the chuck and including a second rotary chuck in axialalignment with the workpiece, releasable gripping means on the secondchuck for grasping an advancing end of the workpiece to move the latterthrough the first chuck when released, said second chuck having a closedend for abutting an end of the workpiece, and stop means forsuccessively limiting retractile shifting movements of said support,constituting a bar provided with abutments spaced apart incorrespondency with specified spacings between areas of the workpiece tobe machined, a cooperative plunger to engage the abutments, and meansmounting the aforesaid constituents of the stop means, one upon theworkpiece positioning support and the other upon a relatively stationarypart of the machine, the plunger including means for selectivelydisengaging it from the abutments.

3. A machine tool comprising in combination,

a rotary chuck having an opening for the receprotating workpiece, atailstock shiitable toward and from the chuck and including a secondrotary chuck in axial alignment with the workpiece, reieasable grippingmeans on the second chuck for grasping an advancing end of the workpieceto move the latter through the first chuck when released, said secondchuck having a closed end for abutting an end of the workpiece, and stopmeans for successively limiting retractile shifting movements of thetailstock, constituting a bar provided with abutments spaced apart incorrespondency with specified spacings between areas of the workpiece tobe machined, a cooperative plunger to engage the abutments, meansmounting the aforesaid constituents of the stop means, one upon theshiftable tailstock and the other upon a relatively stationary part ofthe machine, and means to adjustably shift one constituent of the stopmeans lengthwise of the workpiece.

4. A machine tool comprising in combination, a rotary chuck having anopening for the reception of an elongated workpiece to be machined atpredetermined spaced areas along the length thereof, -said chuckincluding releasable gripping means to enforce rotation of the workpiecewith the chuck while precluding longitudinal shifting of the workpiece,tool means located in close proximity to the chuck and operative toshape the rotating workpiece, a tailstock shiftable toward and from thechuck and including a second rotary chuck in axial alignment with theworkpiece, releasable gripping means on the second chuck for grasping anadvancing end of the workpiece to move the latter through the firstchuck when released, said second chuck having a closed end for abuttingan end of the workpiece, a normally stationary carriage including meansto shiftably support the tailstock, a bar fixed to the carriage andhaving abutments thereon spaced apart in correspondency with specifiedspacings between areas of the workpiece to be machined, and a catchmounted on the shiftable tailstock to releasably engage the abutments ofthe bar in succession as the tailstock is moved to draw the workpiecethrough the first mentioned chuck and past the tool means.

FRANK A. FRITZSCH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 490,863 Conradson Jan. 31, 1893848,578 Thelin Mar. 26, 1907 932,394 Johnson Aug. 24, 1909 945,979Norton Jan. 11, 1910 1,338,742 Lofton May 4, 1920 1,664,757 RandolphApr, 3, 1928 1,895,122 Benedict Jan. 24, 1933 1,907,961 Guillet May 9,1933 1,981,263 Croft Nov. 20, 1934 2,416,612 Cavanagh Feb. 25, 19472,417,132 Schreiber Mar. 11, 1947 FOREIGN PATENTS Number Country Date487,590 Great Britain June 22, 1938 1 559,444 Great Britain Feb. 18,1944

